This invention relates to a tire stud having metal wire embedded in a matrix so that the assembly can be affixed to the perimeter of a tire to provide anti-skid properties to the surface of the tire.
Tire studs using metal spikes are a well known anti-skid device used in rubber tires, as shown in U.S. Pat. Nos. 3,464,476, 3,476,166, 3,719,478 and 3,818,966, and they have been used widely because of the tremendously improved traction they provide on snow and ice surfaces. Use of the studs has allowed automobile travel during snow and ice conditions considered to be extreme. Also the safety of traveling has been increased with resultant decrease in accidents and property damage. These advantages have been overshadowed, though, by the extreme wear the metal spike studs have caused to the road surfaces. The use of these studs is restricted and is even outlawed in some areas because of damage to expressways, tollways, interstate highways, regular streets and roads by the spikes.
The use of wire for anti-skid devices on tires has been proven successful. The wire is inserted in the tire during the manufacture of the tire in the form of coils, U-shapes, twisted wires, mesh, etc., as shown in U.S. Pat. Nos. 2,720,906, 2,777,498, 3,003,534 and 3,053,031. There are advantages and disadvantages in these various methods, the biggest disadvantage being that these tires are a single purpose tire, they are made to be used during periods requiring anti-skid tires. Tires that are made for the addition of studs can be used with or without studs and the manufacture and inventory of tires are simplified and minimized because the tire is not made anti-skid until the ultimate user buys it.
My tire stud which has protruding metal wire embedded in a matrix provides a stud with a relatively flexible tip. The wire which provides the anti-skid properties protrudes into snow and ice to provide traction on these slippery surfaces, but when the tire rolls on the concrete the wire bends with the tire tread and does not penetrate the concrete surface. A single rigid stud such as presently used penetrates the concrete surface because it does not retract into the tire far enough to eliminate its pointed contact with the concrete. This prior stud also is so wear resistant it does not wear down as fast as the tire tread and this results in a still greater protrusion of the stud from the tire with more damage to the concrete surface.
Individually applicable studs made with wires embedded in a matrix provide further advantages in addition to the previously stated advantages in that they can be installed with currently known stud tools into currently known tires; the stud does not build up internal heat or allow entrance of gritty contaminants next to the stud or other such problems that occur when using rigid studs which damage the portion of the tire adjacent to the stud so that the grip of the stud by the tire is weakened and there is possible expulsion of the stud from the tire. My stud is inexpensive to make relative to spike studs in that it can be made by a continuous process which extrudes the matrix around the wires, then cutting the extruded assembly into lengths and forming the stud by shaping the cut length in a suitable forming die. The stud can also be made by injecting the matrix material around a pre-shaped wire assembly such as in injection molding, casting or pouring techniques.
The major object of this invention is to provide a new tire stud which is anti-skid and which will eliminate the problems of extreme road wear.
Another object of this invention is to use wire in the form of a stud to provide anti-skid properties for tires.
Another object of this invention is to embed the wire in a matrix of plastic material to hold the wires in place and to form the stud. This construction has advantages of conforming to the tire and of long life because the heat which is created in the wire during periods of vehicle acceleration or braking does not overheat the tire. The stud works with the tire and generates minimum heat and the plastic does not allow the heat to deteriorate the rubber of the tire around the stud hole.
Another object of this invention is to form a stud wherein the wire is embedded in a matrix of rubber, rubber-like material or so-called plastic resins, any or all of which materials may be resilient or rigid as a means of forming the stud to hold the wires in place.
Another object of this invention is to form a stud wherein the bundle of wires is held together by a tie around the bundles as well as by a matrix material.
Another object of this invention is to form a stud wherein the wire is embedded in a matrix of metal which is faster wearing than the wire, to hold the wire in place and to form the stud, for end uses that require full rigidity of the stud.